Improvement in steam-generators



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UNITED I STATES PATENT GEEICE.

NORMAN W. WHEELER, OF BROOKLYN, NEW YORK.

IMPROVEM ENT IN STEAM-GENERATORS.

Specification forming part of Letters Patent No. 55,405, dated June 5, 1866.

specification, in which Figure 1 represents a sectional plan; Fig. II, awertical section Figs. III and IV, a plan and a section of a modification of some of the details, and Fig. V a plan of a portion of the fire-grate.

My invention relates to boilers of the vertical tubilar type, and its aims are to provide means of access to the crown-sheet and tubes, to facilitate the circulation of water within the boiler, and to provide grate-bars in such form that in a round furnace any section will fit in any part of the grate.

In some instances and under favorable conditions vertical tubular boilers have been worked with good economical results; but in most cases they have been the cause of much trouble, especially when the water used has contained foreign matter, from the difficulty or im possibility of properly cleaning the crownsheet of the furnace and the tubes, and where the boilers were of too great a diameter from defective or languid circulation of the water over the crown-sheet and about the lower parts of the tubes.

To afford access with the ordinary scaling and cleaning tools to the crown-sheet of the furnace D D, I rivet to the sheet a a, at or near the level of the crown-sheet, a series of manhole frames, 0 c c, &c., and cut corresponding apertures through the shell within the frames, and to the head of each frame I fit a manplate, one of which is shown in place at o, the metal of which the frames 0 c, &c., are composed re-entbrcing the shell to the extent to which it was weakened by cutting the apertures through it; and I make these frames and their man-holes and the apertures through the shell to a of sufficient size and number to afford access to all parts of the crown-sheet and to the sides of the furnace D D and to at least the lower portion of the tubes B B. In all examples heretofore within my knowledge there have been at most a few small handholes or plug-holes made in the shell near the top of the furnace, affording access to but small portions of the crown-sheet, the limit to the number and size of such holes being the required longitudinal and circumferential strength ofthe shell but, by my invention, in consequence of the re-enforcement of the shell by the frames 0 c, &c., the apertures may be increased in size to that of an ordinary manhole, or beyond, and in number sufficient to accomplish the result desired without materially weakening the shell.

In Figs. I and III, I have shown the frames c c, &c., as made of plate metal, flanged and riveted, but when proper cast metal can be procured I prefer to rivet on frames such as are shown in Figs. III and IV, with the stays 0 0 0 cast in one with the frame, to reenforce the frame itself as against longitudinal strain upon the boiler. These frames may be made of ordinary cast-iron; but as that metal expands and contracts under the same range of temperatures at widely-different rates as compared with wrought-iron, of which the shell would usually be made, the strain upon the rivets which secure the frame to. the shell would be very great, and would in a short time cause much and annoying leakage; hence i prefer that the frames be made of metal which contracts and expands as near as may be isochronously with the metal of the shellfor instance, malleableized cast-iron, or, by preference, Bessemer steel. These frames, or frames bumped or pressed into the proper form from plates of wrought-iron, I consider to be the mechanical equivalents of those shown at c c 0 85c.

7 To facilitate the circulation of water within the boiler I connect the water-bottom h with the crown-sheet by the circulating-pipe g, which pipe also affords support for the grate.- bearer K K, the pipe g being in or near the middle of the furnace, the obvious effect being a strong current of water passing upward through the pipe 1 when a fire is burning upon the grate j j i 'i, which current will supply water for copious circulation among the lower ends of the tubes B B. In small boilers the pipe 9 will hardly be necessary; but as the diameter is increased so will be increased the usefulness of the said pipe.

Having described my invention, I will proceed to indicate what I consider new and useful, and for which I desire to secure Letters.

Patent, viz:

1. The frames 0 c 0, when arranged around and secured to the shell of a vertical tubular boiler, substantially as and for the purposes described.

2. The circulating-pipe g, in combination with the water-bottom h and the crown-sheet of the furnace D D, when such crown-sheet is also a flue-sheet for the tubes B B;

NORMAN W. YVHEELER.

Witnesses:

F. G. PRINDLE, EDWIN G. Suonnns. 

